Mavic Pro Factory Battery Controller Mod

[beanbubba]

also thanks for that pic marking the serial links, that'll let me do some sniffing to get what commands are being send and received; that's gonna be a big jump in getting the mavic to accept any aftermarket mods on the power side since then i can spoof the output to what the mavic expects the responses to be so no batt errors.

I ordered one of those aftermarket units that Lolo listed in this thread. No idea what to expect, but that's half the fun here

If I was a betting man, and if these aftermarket units actually work, the engineers that crafted them would be insane to so easily brick their own baby. I am now looking forward to getting my hands on one.

 

[beanbubba]

also thanks for that pic marking the serial links, that'll let me do some sniffing to get what commands are being send and received; that's gonna be a big jump in getting the mavic to accept any aftermarket mods on the power side since then i can spoof the output to what the mavic expects the responses to be so no batt errors.

Do you expect the serial link to be a standard async 9600N81N type of connection? Or is it some other type of link? I do not have any experience with this type of gear, but many years on telecom style interfaces.

 

[Mechcondrid]

Do you expect the serial link to be a standard async 9600N81N type of connection? Or is it some other type of link? I do not have any experience with this type of gear, but many years on telecom style interfaces.

honestly i got no idea on that, was just gonna run a protocol sniffer and cycle modes and rates till the stream resolves and starts making some sense; only hiccup might be if its sending raw binary data as opposed to a straight up serial connection with readable text.

 

[Iced Charlie]

Hey Chazz, I was continuing testing and wiring the +/- direct to the battery controller. During testing the battery freaked out and gave an error on the Go4 app. I have not be able to get the error to clear (solid green LED on the middle 2 lights) and there must be a factory reset procedure for the battery controller. Any suggestions?

View attachment 19493 View attachment 19494 View attachment 19495

Any luck recovering 13 synchronous flashes on leds 2&3? On the controller board. or access to old batteries and spare controller boards?

 

[beanbubba]

Any luck recovering 13 synchronous flashes on leds 2&3? On the controller board. or access to old batteries and spare controller boards?

Zero luck

 

[beanbubba]

also thanks for that pic marking the serial links, that'll let me do some sniffing to get what commands are being send and received; that's gonna be a big jump in getting the mavic to accept any aftermarket mods on the power side since then i can spoof the output to what the mavic expects the responses to be so no batt errors.

I mailed out the package Monday via snail mail, you should see it any day now. Let me know when it arrives.

 

[beanbubba]

View attachment 28581 View attachment 28582

The top one is beans board that didnt work the bottom one is one that did work

chazzz, why did you place the jumper wiring shorting the connection to the birdside connector? that would allow you to turn the battery on/off, no??

 

[Mechcondrid]

I mailed out the package Monday via snail mail, you should see it any day now. Let me know when it arrives.

yup will do

 

[chazz]

chazzz, why did you place the jumper wiring shorting the connection to the birdside connector? that would allow you to turn the battery on/off, no??

Yeah as soon as I plug the battery in it turns on because of this. Putting those jumpers in was the way I fixed an issue I had when I modded my P3 battery in the same way. Before I did this when I plugged in a higher capacity battery than the original dji battery’s capacity (4480mah) the P3 would go into autoland at 10% no matter how much of the batteries capacity was left because the board counted down from 4480 mah. So for example if I plugged in a 8000mah battery it would Autoland at 10% even though I’d have around 3520mah left (8000-4480). So I put those jumpers in to send the excess capacity around the board and not through it. It worked and I was able to use the full capacity of whatever battery I had plugged into it. I don’t know if this is the same as the Mavic battery that is set to a non dji battery but I did it anyway.

 

[beanbubba]

Yeah as soon as I plug the battery in it turns on because of this. Putting those jumpers in was the way I fixed an issue I had when I modded my P3 battery in the same way. Before I did this when I plugged in a higher capacity battery than the original dji battery’s capacity (4480mah) the P3 would go into autoland at 10% no matter how much of the batteries capacity was left because the board counted down from 4480 mah. So for example if I plugged in a 8000mah battery it would Autoland at 10% even though I’d have around 3520mah left (8000-4480). So I put those jumpers in to send the excess capacity around the board and not through it. It worked and I was able to use the full capacity of whatever battery I had plugged into it. I don’t know if this is the same as the Mavic battery that is set to a non dji battery but I did it anyway.

Ahhh, got it. You basically have an integrated battery clip in this setup. And as Lolo figured out, even a bricked battery controller will still report voltage back to the Go4 app. I was just hoping for the holy grail of being able to power on/off an external battery with the controller power switch. Thx chazzz.

 

[chazz]

Ahhh, got it. You basically have an integrated battery clip in this setup. And as Lolo figured out, even a bricked battery controller will still report voltage back to the Go4 app. I was just hoping for the holy grail of being able to power on/off an external battery with the controller power switch. Thx chazzz.

Apparently, the difference between a bricked one like lolo’s using and one that isn’t, is the unbricked ones individual cell voltage matches the main voltage if you care about that. I just need the individual cell voltage to be correct because that’s what I look at on the main screen in the app… If you want the “holy grail” you need to find a way to change the mah readout in the go app then the jumpers wouldn’t be needed. Hopefully Mechcondrid can figure it out.

 

[Mechcondrid]

I mailed out the package Monday via snail mail, you should see it any day now. Let me know when it arrives.

i believe it came today just as i was leaving for work; small brown box with printed copy paper labels? was not able to open anything as was literally walking out the door to get in the car and leave.

 

[lolo780]

Looks like another style aftermarket battery is out:

For DJI Mavic Pro/Platinum/Alpine Intelligent Flight LiPo Battery 11.4V 3830mAh | eBay

 

[beanbubba]

Looks like another style aftermarket battery is out:

For DJI Mavic Pro/Platinum/Alpine Intelligent Flight LiPo Battery 11.4V 3830mAh | eBay

I just received my aftermarket battery from china. It was in an unmarked box, no packing material or documentation. Not sure what I want to test first. Any requests?

 

[lolo780]

I just received my aftermarket battery from china. It was in an unmarked box, no packing material or documentation. Not sure what I want to test first. Any requests?

Compare total watt seconds vs percentage against a good DJI battery under the same temperatures.

Back to back zero wind hover test?

 

[beanbubba]

Compare total watt seconds vs percentage against a good DJI battery under the same temperatures.

Back to back zero wind hover test?

I will do a few tests like this before I tear it open, but my ultimate desire is to get the battery controller out and analyzed.

 

[rikiki69]

Have you opened your aftermarket battery ? Is it really different inside ?

 

[chazz]

Hey @beanbubba the last flight i took plugin in a 4's to the battery board i thought i jacked it up. I plugged in the xt60 connector before the balance lead and i couldn't get all the leds to light up and wouldn't show me individual cell % in the app even after i plugged it in the correct way. i unplugged it and hit the power button 5 or 6 times and the next time it worked. I think these boards hold power for a little bit and to drain them i think pushing the power button a few times drains it idk. I don't know much about electronics or circuit boards but I'm thinking there maybe a capacitor on there..

 

[chazz]

Hey @beanbubba the last flight i took plugin in a 4's to the battery board i thought i jacked it up. I plugged in the xt60 connector before the balance lead and i couldn't get all the leds to light up and wouldn't show me individual cell % in the app even after i plugged it in the correct way. i unplugged it and hit the power button 5 or 6 times and the next time it worked. I think these boards hold power for a little bit and to drain them i think pushing the power button a few times drains it idk. I don't know much about electronics or circuit boards but I'm thinking there maybe a capacitor on there..

When you first disconnect the stock cells from the board do you disconnect the balance lead plug first or do you cut the power leads first? I don't remember the way i did it but that might matter as far as brickin the board.

 

[Iced Charlie]

Any luck recovering 13 synchronous flashes on leds 2&3? On the controller board. or access to old batteries and spare controller boards?

I think a phantom 4 is exactly / nearly the same circuit board as the mp. I wonder if like a ups, two circuits could be run in parallel and switch across without loss of power? Maybe.